Abstract:
Based on density functional theory and the crystal structure prediction methods, USPEX and AIRSS, stable
intermediate compounds in the Ni–X (X ¼ B, C, and N) systems and their structures were determined in the
pressure range of 0–400 GPa. It was found that in the Ni–B system, in addition to the known ambientpressure phases, the new nickel boride, Ni2B3-Immm, stabilizes above 202 GPa. In the Ni–C system,
Ni3C-Pnma was shown to be the only stable nickel carbide which stabilizes above 53 GPa. In the Ni–N
system, four new phases, Ni6N-R3, Ni 3N-Cmcm, Ni7N3-Pbca, and NiN2-Pa3, were predicted. For the
new predicted phases enriched by a light-element, Ni2B3-Immm and NiN2-Pa3, mechanical and
electronic properties have been studied.
